Closed daonvshu closed 1 year ago
To programmatically expand or collapse a node, use the toggleExpansion method of the TreeViewController
To get the TreeViewController
, wrap the TreeViewState
inside a GlobalKey
like final globalKey = GlobalKey<TreeViewState>()
, and then get the controller from the currentState like this globalKey.currentState?.controller;
Full code sample to use the TreeViewController
:
class _MyHomePageState extends State<MyHomePage> {
final globalKey = GlobalKey<TreeViewState>();
TreeViewController? get controller => globalKey.currentState?.controller;
final tree = TreeNode<String>();
void toggleExpansion(String nodePath) {
final node = controller?.elementAt(nodePath);
if (node != null) controller?.toggleExpansion(node);
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: Text(widget.title)),
body: TreeView.simple<String>(
key: globalKey,
tree: tree,
builder: (context, level, item) => ListTile(
title: Text("Item ${item.level}-${item.key}"),
),
),
);
}
}
hi, you didn't really answer the first question
expand all child nodes
if you could respond to this that'd be great
@kespaldon right now there is no builtin method to expand all the children of a node. So you will have to recursively iterate through the children, and expand them. I will add a utility method to handle expansion of all children in the next release. For the time being you can use this handy extension to achieve the same.
extension TreeControllerX<Data, Tree extends ITreeNode<Data>>
on TreeViewController {
/// Utility method for programmatically expanding all the child nodes. By default
/// only the immediate children of the node will be expanded.
/// Set [recursive] to true for expanding all the child nodes until the leaf is
/// reached.
void expandAllChildren(Tree node, {bool recursive = false}) {
for (final child in node.childrenAsList) {
toggleExpansion(child as Tree);
if (child.childrenAsList.isNotEmpty) expandAllChildren(child);
}
}
}
Hi, Is there any way to expand all child nodes or specified node after all view build is complete? I changed the 'isExpanded' property of the TreeNode to true but it had no effect.